Manufacturing method of photomask, method for optical proximity correction, and manufacturing method of semiconductor device

ABSTRACT

A manufacturing method of a photomask by which a resist pattern corresponding to a pattern with designed values can be formed, a method for optical proximity correction, and a manufacturing method of a semiconductor device are provided. Proximity design features that are close to each other and estimated to violate a mask rule check are extracted. In the proximity design features, correction prohibited regions where optical proximity correction is not carried out are set based on the distance between the features obtained from the extracted proximity design features and the resolution of an exposure device. Optical proximity correction is carried out on the proximity design features with the correction prohibited regions excluded to obtain corrected proximity patterns. A predetermined mask material is patterned by carrying out electron beam lithography based on the corrected proximity pattern data.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure of Japanese Patent Application No. 2011-7839 filed onJan. 18, 2011 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND

The present invention relates to manufacturing methods of photomasks,methods for optical proximity correction, and manufacturing methods ofsemiconductor devices and in particular to a manufacturing method of aphotomask for forming hole features and line features, a method foroptical proximity correction used to manufacture such a photomask, and amanufacturing method of a semiconductor device using this photomask.

In the manufacture of a semiconductor device, a semiconductor element, awiring, or the like is formed by repeating the following steps: a stepof forming a predetermined film, such as an insulating film or aconductive film, over a semiconductor substrate, a step of carrying outprocessing, such as etching, on the film, and the other like steps.Before this processing is carried out, a resist pattern is formed over apredetermined film by a lithography process. In the lithography process,it is important to form a desired resist pattern so that desired patterndimensions and shape can be obtained by processing such as etching.

In conjunction with the microminiaturization of patterns, there is atendency of the shape or dimensions of a resist pattern to deviate fromthe shape or dimensions of the pattern with designed values. When aphotomask is manufactured, for this reason, processing is carried out tocorrect the data of the pattern of the photomask to make a resistpattern actually formed over a semiconductor substrate agree with adesired finished shape. This processing is designated as opticalproximity correction (OPC).

A photomask pattern is determined based on data corrected by thisoptical proximity correction and there are model-based OPC andrule-based OPC as techniques therefor. In model-based OPC, a photomaskpattern is determined by taking the following procedure: a designpattern is divided into small sides; each side is corrected by opticalproximity correction built based on experimental values; an actuallydelineated resist pattern is estimated by shape simulation using thecorrected pattern; and pattern deformation and shape simulation for theresist pattern are repeated until a desired resist pattern is obtained.In rule-based OPC, meanwhile, a photomask pattern is determined bycorrecting pattern data with designed values with a preset amount ofcorrection for optical proximity correction.

A photomask is manufactured based on data of a photomask pattern finallydetermined as mentioned above. First, a resist film for electron beamexposure over a light shield film formed over the surface of a glassplate is scanned with an electron beam based on the data and a layoutpattern is thereby drawn. Subsequently, the resist film for electronbeam exposure is subjected to predetermined development and a resistpattern corresponding to the layout pattern is thereby formed.Subsequently, the light shield film is subjected to etching using theresist pattern as a mask and a photomask is thereby formed.

[Patent Document 1]

-   Japanese Unexamined Patent Publication No. 2000-181046

[Patent Document 2]

-   Japanese Unexamined Patent Publication No. 2002-258459

SUMMARY

As mentioned above, a photomask is manufactured by carrying out electronbeam lithography based on data of a determined pattern. As the result ofoptical proximity correction being carried out, the opening size of ahole feature tends to be increased relative to pattern data withdesigned values, especially, in places where hole features are close toeach other. In addition, the end portions of line features close to eachother tend to be increased in size in places where the line features areclose to each other. For this reason, in a photomask pattern thatunderwent optical proximity correction, hole features or the endportions of line features are further brought close to each other.

In places where features are too close to each other, the following maytake place even though the features are positioned separately from eachother by data: when electron beam lithography is carried out based onthe data, features actually formed as a photomask bond to each other orcannot be accurately drawn. That is, an area where features are close toeach other cannot be stably resolved.

To avoid these problems in advance, it is checked whether or not aphotomask pattern that underwent optical proximity correction can beactually and stably formed as a photomask pattern based on the data ofthe pattern. This check is designated a mask rule check MRC).

With respect to a place where it is determined by this mask rule checkthat patterns cannot be stably resolved into a photomask, the followingprocessing is carried out: the edges of portions of the features areretreated so that the features are separated from each other to adistance at which they can be resolved or part of the features istrimmed. That is, the data on a photomask pattern so determined that adesired resist pattern is formed over a semiconductor substrate ischanged with respect to part of the pattern before the photomask is madebecause of limitations imposed when the photomask is made. Examples ofdocuments disclosed in this technical field include Patent Document 1and Patent Document 2.

For this reason, the following may take place in photomasks made basedon corrected data: for example, the size of a resist pattern over asemiconductor substrate is reduced and a desired resist pattern cannotbe obtained. Since a resist pattern with a desired size and the likecannot be obtained, the following may take place: a sufficient depth offocus cannot be ensured and it is difficult to accurately resolve apattern on resist applied to a stepped base material.

The invention has been made to solve the above problems. It is an objectthereof to provide a manufacturing method of a photomask by which aresist pattern corresponding to a pattern with designed values can beformed over a semiconductor substrate. It is another object thereof toprovide a method for optical proximity correction used in thismanufacturing method of a photomask. It is further another objectthereof to provide a manufacturing method of a semiconductor device towhich such a photomask is applied.

A manufacturing method of a photomask of the invention is forphotoengraving a predetermined pattern in a photosensitive material filmover a semiconductor substrate and includes the following steps. At astep, proximity design features close to each other are extracted in adesired pattern with designed values. The proximity design features willbe brought too close to each other when optical proximity correction iscarried and cannot be stably resolved as a photomask pattern and arethus estimated to violate a mask rule check. At a step, correctionprohibited regions in which optical proximity correction is not carriedout are set in the proximity design features based on the following: thedistance between the features obtained from the extracted proximitydesign features and a resolution obtained from the wavelength of theexposure light and the numerical aperture of an exposure device. At astep, the proximity design features are subjected to optical proximitycorrection with the correction prohibited regions excluded and correctedproximity features are thereby determined. At a step, electron beamlithography is carried out based on the corrected proximity patterns topattern a predetermined mask material.

A method for optical proximity correction of the invention is foroptical proximity correction applied to the manufacture of a photomaskfor photoengraving and includes the following steps. At a step,proximity design features close to each other are extracted in a desiredpattern with designed values. The proximity design features will bebrought too close to each other when optical proximity correction iscarried out and cannot be stably resolved as a photomask pattern and arethus estimated to violate a mask rule check. At a step, correctionprohibited regions in which optical proximity correction is not carriedout are set in the proximity design features based on the following: thedistance between the features obtained from the extracted proximitydesign features and a resolution obtained from the wavelength of theexposure light and the numerical aperture of an exposure device. At astep, the proximity design features are subjected to optical proximitycorrection with the correction prohibited regions excluded and correctedproximity features are thereby determined.

A manufacturing method of a semiconductor device of the inventionincludes the following steps. At a step, a film to be processed isformed over the main surface of a semiconductor substrate. At a step,the surface of the film to be processed is coated with resist. Theresist is photoengraved using a photomask containing proximity photomaskpatterns close to each other. At a step, the photoengraved resist issubjected to development to form resist patterns corresponding to theproximity photomask patterns. At a step, the film to be processed isprocessed using the resist patterns as a mask and a film-to-be-processedpattern corresponding to the proximity photomask patterns is formed overthe film to be processed.

The photomask used here is formed by taking the following procedure.Proximity design features that will be brought close to each other whenoptical proximity correction is carried out and cannot be stablyresolved as a photomask pattern and are thus estimated to violate a maskrule check are extracted. Correction prohibited regions in which opticalproximity correction is not carried out are set in the extractedproximity design features based on the following: the distance betweenthe features obtained from the proximity design patterns and aresolution obtained from the wavelength of the exposure light and thenumerical aperture of an exposure device. The proximity design featuresare subjected to optical proximity correction with the correctionprohibited regions excluded and corrected proximity features are therebyobtained. Electron beam lithography is carried out based on the obtainedcorrected proximity pattern data.

According to the manufacturing method of a photomask or the method foroptical proximity correction of the invention, a target patterning shapeof a film to be processed can be obtained over a semiconductor substratewithout violating a mask rule check. To do this, the following procedureis taken. Correction prohibited regions in which optical proximitycorrection is not carried out are set in the following patterns beforeoptical proximity correction is carried out: features that are close toeach other and estimated to violate a mask rule check after opticalproximity correction is carried out. Then optical proximity correctionis carried out.

In pattern correction having the same effect as mentioned above, thefollowing can be implemented: in model-based OPC processing, initialdivided side length can be made very small. In this case, however, theOPC processing calls for a huge amount of time and the amount of drawingdata also becomes enormous. In addition, photomask drawing also callsfor a huge amount of time. Therefore, this is not practical. In theinvention, meanwhile, only proximity design features are subjected toprocessing different from conventional cases and this problem does notarise.

According to the manufacturing method of a semiconductor device of theinvention, the following can be implemented when hole features, linefeatures, and the like are formed in resist by applying theabove-mentioned photomask: a desired resist pattern can be obtained anda depth of focus can be ensured and thus the process margin inphotoengraving can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating a method for optical proximitycorrection in a first embodiment of the invention;

FIG. 2 is a drawing explaining a method for optical proximity correctionin the case of hole features in the embodiment;

FIG. 3 is a drawing explaining a method for optical proximity correctionin the case of line features in the embodiment;

FIG. 4 is a drawing explaining optical proximity correction in the caseof hole features in a comparative example;

FIG. 5 is a drawing explaining optical proximity correction in the caseof line features in a comparative example;

FIG. 6 is a plan view illustrating a step in a manufacturing method of aphotomask to which a method for optical proximity correction in a secondembodiment of the invention is applied;

FIG. 7 is a plan view illustrating a step carried out after the stepillustrated in FIG. 6 in the embodiment;

FIG. 8 is a plan view illustrating a step carried out after the stepillustrated in FIG. 7 in the embodiment;

FIG. 9 is a plan view illustrating a photomask made based on dataobtained from the step illustrated in FIG. 8 in the embodiment;

FIG. 10 is a plan view illustrating a resist pattern subjected tophotoengraving and development using the photomask illustrated in FIG. 9in the embodiment;

FIG. 11 is a graph indicating the relation between CD value and defocusamount in the embodiment;

FIG. 12 is a plan view illustrating a step in a manufacturing method ofa photomask to which a method for optical proximity correction in athird embodiment of the invention is applied;

FIG. 13 is a plan view illustrating a step carried out after the stepillustrated in FIG. 12 in the embodiment;

FIG. 14 is a plan view illustrating a step carried out after the stepillustrated in FIG. 13 in the embodiment;

FIG. 15 is a plan view illustrating a photomask made based on dataobtained from the step illustrated in FIG. 14 in the embodiment;

FIG. 16 is a plan view illustrating a resist pattern subjected tophotoengraving and development using the photomask illustrated in FIG.15 in the embodiment;

FIG. 17 is a plan view illustrating a step in a manufacturing method ofa photomask to which a method for optical proximity correction in afourth embodiment of the invention is applied;

FIG. 18 is a plan view illustrating a step carried out after the stepillustrated in FIG. 17 in the embodiment;

FIG. 19 is a plan view illustrating a step carried out after the stepillustrated in FIG. 18 in the embodiment;

FIG. 20 is a plan view illustrating a photomask made based on dataobtained from the step illustrated in FIG. 19 in the embodiment;

FIG. 21 is a plan view illustrating a resist pattern subjected tophotoengraving and development using the photomask illustrated in FIG.20 in the embodiment;

FIG. 22 is a plan view illustrating a step in a manufacturing method ofa photomask to which a method for optical proximity correction in afifth embodiment of the invention is applied;

FIG. 23 is a plan view illustrating a step carried out after the stepillustrated in FIG. 22 in the embodiment;

FIG. 24 is a plan view illustrating a step carried out after the stepillustrated in FIG. 23 in the embodiment;

FIG. 25 is a plan view illustrating a photomask made based on dataobtained from the step illustrated in FIG. 24 in the embodiment;

FIG. 26 is a plan view illustrating a resist pattern subjected tophotoengraving and development using the photomask illustrated in FIG.25 in the embodiment;

FIG. 27 is a plan view illustrating a step in a manufacturing method ofa photomask to which a method for optical proximity correction in asixth embodiment of the invention is applied;

FIG. 28 is a plan view illustrating a step carried out after the stepillustrated in FIG. 27 in the embodiment;

FIG. 29 is a plan view illustrating a step carried out after the stepillustrated in FIG. 28 in the embodiment;

FIG. 30 is a plan view illustrating a photomask made based on dataobtained from the step illustrated in FIG. 29 in the embodiment;

FIG. 31 is a plan view illustrating a resist pattern subjected tophotoengraving and development using the photomask illustrated in FIG.30 in the embodiment;

FIG. 32 is a plan view explaining a manufacturing method of asemiconductor device to which a photomask in a seventh embodiment of theinvention is applied;

FIG. 33 is a partial sectional perspective view illustrating a step inthe manufacturing method of a semiconductor device illustrated in FIG.32 in the embodiment;

FIG. 34 is a partial sectional perspective view illustrating anotherstep in the manufacturing method of a semiconductor device illustratedin FIG. 32 in the embodiment; and

FIG. 35 is a partial sectional perspective view illustrating furtheranother step in the manufacturing method of a semiconductor deviceillustrated in FIG. 32 in the embodiment.

DETAILED DESCRIPTION First Embodiment

Description will be given to the overview of a method for opticalproximity correction carried out on a pattern (data) with designedvalues used to manufacture a photomask and a manufacturing method of thephotomask using this method with model-based OPC taken as an example.FIG. 1 is a flowchart of the method for optical proximity correction. AtStep S1, as illustrated in FIG. 1, proximity design features close toeach other are extracted. The proximity design features will be furtherbrought close to each other when optical proximity correction is carriedout; and they cannot be stably resolved as a photomask pattern at theclose portions and are estimated to violate a mask rule check. At StepS2, subsequently, it is determined whether the extracted proximitydesign features are hole features or line features.

Subsequently, correction prohibited regions in which optical proximitycorrection is not carried out are set in the extracted proximity designfeatures. This will be described first with respect to a case where theproximity design features are hole features. As illustrated in FIG. 2,it will be assumed that the extracted proximity design features are ahole feature DHA, HA in the length of each side and a hole feature DHB,HB in the length of each side. This length HA (HB) of each side isequivalent to the opening diameter of a target hole with designedvalues.

At Step S3, subsequently, the distance S between the corners closest toeach other in the hole feature DHA and the hole feature DHB iscalculated as shown at the upper tier of FIG. 2. In addition, thedistance (pitch P) between the center of the hole feature DHA and thecenter of the hole feature DHB is calculated. Further, a resolution Re(k1×λ/NA) is calculated based on the wavelength λ of the exposure lightand the numerical aperture NA of an exposure device and aprocess-dependent parameter k1.

At Step S4, subsequently, it is determined, for example, whether or notthe pitch P is equal to or larger than 50% of the resolution Re and thedistance S is equal to or smaller than three times the length HA (HB) ofeach side of the hole feature. When these conditions are met, thefollowing processing is carried out Step S7 as shown at the middle tierof FIG. 2: a correction prohibited region PRA is set in the hole featureDHA and a correction prohibited region PRB is set in the hole featureDHB.

The length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB aredetermined based on the arrangement relation between the hole featureDHA and the hole pattern DHB in the XY plane. Specifically, there arethe following cases: cases where the length AX in the X-axis directionof the correction prohibited region PRA and the length AY in the Y-axisdirection thereof are set to an identical value; and cases where thelength AX in the X-axis direction and the length AY in the Y-axisdirection are set to different values. For example, a value of 2 nm to(⅔)×HA nm or so is set for these lengths. In addition, there are thefollowing cases: cases where the length BX in the X-axis direction ofthe correction prohibited region PRB and the length BY in the Y-axisdirection thereof are set to an identical value; and cases where thelength BX in the X-axis direction and the length BY in the Y-axisdirection are set to different values. For example, a value of 2 nm to(⅔)×HB nm or so is set for these lengths.

At Step S8, subsequently, optical proximity correction is carried out onthe hole feature DHA and the hole feature DHB with the correctionprohibited regions PRA, PRB excluded. At Step S9, subsequently, shapesimulation for a resist pattern is carried out based on the holefeatures that underwent optical proximity correction. At Step S10,subsequently, it is determined whether or not the resist patternobtained by the shape simulation is sufficiently equivalent to a desiredresist pattern based on designed values. When the desired resist patternhas not been obtained, the processing of Step S8 and Step S9 is repeateduntil the desired resist pattern is obtained.

Thus the following is implemented as shown at the lower tier of FIG. 2:with respect to the hole feature DHA, a corrected hole feature CHA isobtained with the correction prohibited region PRA excluded; and withrespect to the hole feature DHB, a corrected hole feature CHB isobtained with the correction prohibited region PRB excluded. The shapeof a resist pattern RHA obtained based on the corrected hole feature CHAsubstantially agrees with the following shape: the shape of a resistpattern inscribed to the four sides of the hole feature DHA, obtainedbased on the hole feature DHA before the correction prohibited regionPRA is set.

The shape of a resist pattern RHB obtained based on the corrected holefeature CHB substantially agrees with the following shape: the shape ofa resist pattern inscribed to the four sides of the hole feature DHB,obtained based on the hole feature DHB before the correction prohibitedregion PRB is set. The optimization of optical proximity correction onhole features close to each other is completed as mentioned above (StepS11).

Description will be give to a case where the features close to eachother are line features. As illustrated in FIG. 3, it will be assumedthat the extracted proximity design features are a line feature DLA, WAin width and a line feature DLB, WB in width. This width WA (WB) isequivalent to the width of a target line with designed values.

At Step S5, subsequently, the distance S between the corners closest toeach other in the line feature DLA and the line feature DLB iscalculated as shown at the upper tier of FIG. 3. In addition, aresolution Re (k1×λ/NA) is calculated based on the wavelength λ of theexposure light and the numerical aperture NA of an exposure device and aprocess-dependent parameter k1.

At Step S6, subsequently, it is determined, for example, whether or notthe distance S is not less than 50% of the resolution Re and not morethan 300% thereof. When this condition is met, the following processingis carried out at Step S7 as shown at the middle tier of FIG. 3: acorrection prohibited region PRA is set in the line feature DLA and acorrection prohibited region PRB is set in the line feature DLB.

The length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB aredetermined based on the arrangement relation between the line featureDLA and the line feature DLB in the XY plane. Specifically, there arethe following cases: cases where the length AX in the X-axis directionof the correction prohibited region PRA and the length AY in the Y-axisdirection thereof are set to an identical value; and cases where thelength AX in the X-axis direction and the length AY in the Y-axisdirection are set to different values. For example, a value of 2 nm to(⅔)×WA nm or so is set for these lengths. In addition, there are thefollowing cases: cases where the length BX in the X-axis direction ofthe correction prohibited region PRB and the length BY in the Y-axisdirection thereof are set to an identical value; and cases where thelength BX in the X-axis direction and the length BY in the Y-axisdirection are set to different values. For example, a value of 2 nm to(⅔)×WB nm or so is set for these lengths.

At Step S8, subsequently, optical proximity correction is carried out onthe line feature DLA and the line feature DLB with the correctionprohibited regions PRA, PRB excluded. At Step S9, subsequently, shapesimulation for a resist pattern is carried out based on the linefeatures that underwent optical proximity correction. At Step S10,subsequently, it is determined whether or not the resist patternobtained by the shape simulation is sufficiently equivalent to a desiredresist pattern based on designed values. When the desired resist patternhas not been obtained, the processing of Step S8 and Step S9 is repeateduntil the desired resist pattern is obtained.

Thus the following is implemented as shown at the lower tier of FIG. 3:with respect to the line feature DLA, a corrected line feature CLA isobtained with the correction prohibited region PRA excluded; and withrespect to the line feature DLB, a corrected line feature CLB isobtained with the correction prohibited region PRB excluded. The shapeof a resist pattern RLA obtained based on the corrected line feature CLAsubstantially agrees with the following shape: the shape of a resistpattern in contact with the sides of the line feature DLA in thedirection of length and a side of an end portion thereof, obtained basedon the line feature DLA before the correction prohibited region PRA isset.

The shape of a resist pattern RLB obtained based on the corrected linefeature CLB substantially agrees with the following shape: the shape ofa resist pattern in contact with the sides of the line feature DLB inthe direction of length and a side of an end portion, obtained based onthe line feature DLB before the correction prohibited region PRB is set.The optimization of optical proximity correction on line features closeto each other is completed as mentioned above (Step S11).

A photomask is formed by taking the following procedure (Step S12): aresist film for electron beam exposure over a light shield film isscanned with an electron beam based on the data of a desired patterncontaining the hole features or the line features for which theoptimization of optical proximity correction has been completed; thepattern is thereby drawn and is subjected to predetermined development;and the light shield film (mask material) is subjected to etchingprocessing.

The photomask manufactured by applying the above-mentioned method foroptical proximity correction brings about the following advantage: adesired resist pattern (the patterning shape of a film to be processedover a semiconductor substrate) can be obtained from target designedvalues without violating a mask rule check.

This will be described based on the relation with a manufacturing methodof a photomask in a comparative example. First, description will begiven to a case of hole features. As illustrated at the upper tier ofFIG. 4, optical proximity correction is carried out on a design holefeature DHA and a design hole feature DHB close to each other and acorrected hole feature CCHA and a corrected hole feature CCHB arethereby obtained. If it is impossible to stably resolve the correctedhole feature CCHA and the corrected hole feature CCHB as a photomask atthis time and a mask rule check is violated (in the broken line frame),the following measure is taken: the patterns are corrected so that themask rule check is not violated.

That is, the means illustrated at the middle tier of FIG. 4 is taken.Specifically, in the corrected hole feature CCHA, the area CAXY on theside where it is opposed to the corrected hole feature CCHB is retreatedand brought away from the corrected hole feature CCHB. In the correctedhole feature CCHB, meanwhile, the area CBXY the side where it is opposedto the corrected hole feature CCHA is retreated and brought away fromthe corrected hole feature CCHA.

For this reason, the following takes place even though the correctedhole feature CCHA (CCHB) is initially set so that a resist patterninscribed to the four sides of the design hole feature DHA (DHB) can beobtained: as illustrated at the lower tier of FIG. 4, a resist patternCRHA (CRHB) that is not inscribed to, for example, at least two sides ofthe hole feature DHA (DHB) (in the broken line frames) is formed and adesired resist pattern cannot be obtained.

Description will be given to a case of line features. As illustrated atthe upper tier of FIG. 5, optical proximity correction is carried out ona design line feature DLA and a design line feature DLB close to eachother and a corrected line feature CCLA and a corrected line featureCCLB are thereby obtained. If it is impossible to stably resolve thecorrected line feature CCLA and the corrected line feature CCLB as aphotomask and a mask rule check is violated (in the broken line frame),the following measure is taken: the patterns are corrected by thetechniques disclosed in Patent Documents 1 and 2 so that the mask rulecheck is not violated.

That is, the means illustrated at the middle tier of FIG. 5 is taken.Specifically, in the corrected line feature CCLA, the area CAXY on theside where it is opposed to the corrected line feature CCLB is retreatedand brought away from the corrected line feature CCLB. In the correctedline feature CCLB, meanwhile, the area CBXY on the side where it isopposed to the corrected line feature COLA is retreated and brought awayfrom the corrected line feature CCLA.

For this reason, a problem arises even though the corrected line featureCCLA (CCLB) is initially set so that the following can be implemented: aresist pattern in contact with the two side of the design line featureDLA (DLB) in the direction of length and a side of an end portion can beobtained. As illustrated at the lower tier of FIG. 5, the followingresist pattern is formed: a resist pattern CRLA (CRLB) that is incontact with, for example, only two sides of the design line feature DLA(DLB) in the direction of length but not in contact with a side of anend portion (in the broken line frames). Thus a desired resist patterncannot be obtained.

As mentioned above, the following measure is taken in hole features orline features close to each other in the manufacturing method of aphotomask in the comparative example: part of the patterns of thephotomask is corrected so that a mask rule check is not violated. Forthis reason, a desired resist pattern (the patterning shape of a film tobe processed over a semiconductor substrate) with target designed valuescannot be obtained.

In the above-mentioned manufacturing method of a photomask, meanwhile,the following measure is taken in features that are close to each otherand estimated to violate a mask rule check after optical proximitycorrection is carried out: before the optical proximity correction iscarried out, correction prohibited regions in which optical proximitycorrection is not carried out are set and then optical proximitycorrection is carried out. This makes it possible to obtain a resistpattern (the patterning shape of a film to be processed over asemiconductor substrate) with target designed values without violating amask rule check.

Second Embodiment

Description will be given to a more concrete first example of themanufacturing method of a photomask. As illustrated in FIG. 6, first, itwill be assumed that the following hole features are hole features thatare close to each other and estimated to violate a mask rule check whenoptical proximity correction is carried out: a hole feature DHA, HA (=75nm) in the length of each side and a hole feature DHB, HB (=75 nm) inthe length of each side. In addition, it will be assumed that the angleθ1 formed by a line segment connecting the center of the hole featureDHA and the center of the hole feature DHB and the X-axis is 45°.

Subsequently, the distance S (=21 nm) between the corners closest toeach other in the hole feature DHA and the hole feature DHB iscalculated. In addition, the distance (pitch P) between the center ofthe hole feature DHA and the center of the hole feature DHB iscalculated. Further, a resolution Re (k1×λ/NA) is calculated based onthe wavelength λ of the exposure light and the numerical aperture NA ofan exposure device and a process-dependent parameter k1.

Subsequently, for example, it is determined whether or not the pitch Pis equal to or larger than 50% of the resolution Re and the distance Sis equal to or smaller than three times the length HA (HB) of each sideof each hole feature. When these conditions are met, the followingmeasure is taken as illustrated in FIG. 7: a correction prohibitedregion PRA is set in the hole feature DHA and a correction prohibitedregion PRB is set in the hole feature DHB.

The length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB aredetermined based on the arrangement relation between the hole featureDHA and the hole feature DHB in the XY plane. Since the angle θ1 is 45′,in this case, the following measure is taken: the length AX in theX-axis direction of the correction prohibited region PRA and the lengthAY in the Y-axis direction thereof are set to an identical value (10nm); and the length BX in the X-axis direction of the correctionprohibited region PRB and the length BY in the Y-axis direction thereofare also set to an identical value (10 nm).

Subsequently, optical proximity correction is carried out on the holefeature DHA and the hole feature DHB with the correction prohibitedregions PRA, PRB excluded. Then shape simulation for a resist pattern iscarried out based on the hole features that underwent the opticalproximity correction. In model-based OPC, as mentioned above, thepattern deformation and the shape simulation for a resist pattern arerepeated until a resist pattern with target designed values is obtained.Thus the following processing is carried out as illustrated in FIG. 8:with respect to the hole feature DHA, a corrected hole feature CHA isobtained with the correction prohibited region PRA excluded; and withrespect to the hole feature DHB, a corrected hole feature CHB isobtained with the correction prohibited region PRB excluded.

Subsequently, a photomask is manufactured by carrying out electron beamlithography based on the data of the obtained corrected hole feature CHAand the data of the obtained corrected hole feature CHB. First, a resistfilm for electron beam exposure over a light shield film formed over thesurface of a glass plate is scanned with an electron beam based on thedata. A predetermined pattern containing the corrected hole feature CHAand the corrected hole feature CHB is thereby drawn. Subsequently, theresist film for electron beam exposure is subjected to predetermineddevelopment and a resist pattern corresponding to the corrected holefeature CHA and the corrected hole feature CHB is thereby formed.

Subsequently, the light shield film is etched using the resist patternas a mask. As a result, as illustrated in FIG. 9, a photomask ismanufactured. The photomask is obtained by forming a photomask holefeature MHA corresponding to the corrected hole feature CHA and aphotomask hole feature MHB corresponding to the corrected hole featureCHB in the light shield film SF. Using the thus manufactured photomaskM, resist applied to a semiconductor substrate is subjected tophotoengraving and development. As illustrated in FIG. 10, consequently,a resist pattern RHA and a resist pattern RHB are formed in the resist(positive resist) R.

In the above-mentioned manufacturing method of a photomask, thefollowing procedure is taken. Features that are close to each other andare estimated to violate a mask rule check after optical proximitycorrection is carried out are extracted. In these features, correctionprohibited regions in which optical proximity correction is not carriedout are set based on the arrangement relation between the features.Thereafter, optical proximity correction is carried out. Especially, inthis case, the angle θ1 is 45° and thus the length in the X-axisdirection and the length in the Y-axis direction of each of thecorrection prohibited regions PRA, PRB are set to an identical value. Asa result, a photomask that makes it possible to obtain a target resistpattern (the patterning shape of a film to be processed over asemiconductor substrate) without violating a mask rule check can beobtained.

With the above-mentioned photomask, a desired resist pattern based ondesigned values can be obtained and thus it is possible to ensure adepth of focus (DOF). This will be described using a conventional methodas well. FIG. 11 is a graph indicating the relation between CD (CriticalDimension) value and defocus amount. The embodiment of this inventionshows the result obtained in the above-mentioned case where a photomaskin which the length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB are setto 10 nm. The conventional method shows the result obtained when aphotomask manufactured by the technique illustrated in FIG. 4 is used.

It will be assumed that the target CD value is, for example, 75 nm. Inthis case, it is seen from FIG. 11 that the target CD value is achievedin the example (square). It is also seen that in the embodiment of theinvention, the descent of the CD value is gentle with just focus (0 nm)at the center and a sufficient depth of focus can be ensured.

Meanwhile, it is seen that the following takes place in the conventionalmethod (triangle): the target CD value cannot be achieved; the descentof the CD value is steeper than in the embodiment of the invention withjust focus (0 nm) at the center and a sufficient depth of focus cannotbe ensured.

Third Embodiment

Description will be given to a more concrete second example of themanufacturing method of a photomask. As illustrated in FIG. 12, first,it will be assumed that the following hole features are hole featuresthat are close to each other and estimated to violate a mask rule checkwhen optical proximity correction is carried out: a hole feature DHA, HA(=75 nm) in the length of each side and a hole feature DHB, HB (=75 nm)in the length of each side. In addition, it will be assumed that theangle θ2 formed by a line segment connecting the center of the holefeature DHA and the center of the hole feature DHB and the X-axis is35°.

Subsequently, the distance S (=16 nm) between the corners closest toeach other in the hole feature DHA and the hole feature DHB iscalculated. In addition, the distance (pitch P) between the center ofthe hole feature DHA and the center of the hole feature DHB iscalculated. Further, a resolution Re (k1×λ/NA) is calculated based onthe wavelength λ of the exposure light and the numerical aperture NA ofan exposure device and a process-dependent parameter k1.

Subsequently, for example, it is determined whether or not the pitch Pis equal to or larger than 50% of the resolution Re and the distance Sis equal to or smaller than three times the length HA (HB) of each sideof each hole feature. When these conditions are met, the followingmeasure is taken as illustrated in FIG. 13: a correction prohibitedregion PRA is set in the hole feature DMA and a correction prohibitedregion PRB is set in the hole feature DHB.

The length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB aredetermined based on the arrangement relation between the hole featureDHA and the hole feature DHB in the XY plane. Since the angle θ2 is 35°,in this case, the following measure is taken: the length AY (40 nm) inthe Y-axis direction of the correction prohibited region PRA is set to avalue larger than the length AX (10 nm) in the X-axis direction thereof;and the length BY (40 nm) in the Y-axis direction of the correctionprohibited region PRB is set to a value larger than the length BX (10nm) in the X-axis direction thereof.

Subsequently, optical proximity correction is carried out on the holefeature DHA and the hole feature DHB with the correction prohibitedregions PRA, PRB excluded. Then shape simulation for a resist pattern iscarried out based on the hole features that underwent the opticalproximity correction. In model-based OPC, as mentioned above, thepattern deformation and the shape simulation for a resist pattern arerepeated until a target resist pattern is obtained. Thus the followingprocessing is carried out as illustrated in FIG. 14: with respect to thehole feature DHA, a corrected hole feature CHA is obtained with thecorrection prohibited region PRA excluded; and with respect to the holefeature DHB, a corrected hole feature CHB is obtained with thecorrection prohibited region PRB excluded.

Subsequently, a predetermined pattern containing the corrected holefeature CHA and the corrected hole feature CHB is drawn by scanning aresist film for electron beam exposure over a light shield film formedover the surface of a glass plate with an electron beam. This scanningis carried out based on the data of the obtained corrected hole featureCHA and the data of the obtained corrected hole feature CHB.Subsequently, a resist pattern corresponding to the corrected holefeature CHA and the corrected hole feature CHB is formed by subjectingthe resist film for electron beam exposure to predetermined development.

Subsequently, the following photomask is manufactured by etching thelight shield film using this resist pattern as a mask as illustrated inFIG. 15: a photomask M in which a photomask hole feature MHAcorresponding to the corrected hole feature CHA and a photomask holefeature MHB corresponding to the corrected hole feature CHB are formedin the light shield film SF. Using the thus manufactured photomask M,resist applied to a semiconductor substrate is subjected tophotoengraving and development. As illustrated in FIG. 16, consequently,a resist pattern RHA and a resist pattern RHB are formed in the resist(positive resist) R.

In the above-mentioned manufacturing method of a photomask, thefollowing procedure is taken. Features that are close to each other andare estimated to violate a mask rule check after optical proximitycorrection is carried out are extracted. In these features, correctionprohibited regions in which optical proximity correction is not carriedout are set based on the arrangement relation between the features.Thereafter, optical proximity correction is carried out. Especially, inthis case, the angle θ2 is 35° and thus the length in the X-axisdirection and the length in the Y-axis direction of each of thecorrection prohibited regions PRA, PRB are set to different values. As aresult, a photomask that makes it possible to obtain a target resistpattern (the patterning shape of a film to be processed over asemiconductor substrate) without violating a mask rule check can beobtained. In addition, since a desired resist pattern based on designedvalues is obtained, it is possible to ensure a sufficient depth offocus.

Fourth Embodiment

Description will be given to a more concrete third example of themanufacturing method of a photomask. As illustrated in FIG. 17, it willbe assumed that the followings are line features that are close to eachother and estimated to violate a mask rule check when optical proximitycorrection is carried out: a line feature DLA, WA in width and a linefeature DLB, WB in width. In addition, it will be assumed that the angleθ1 formed by a line segment connecting the corners closest to each otherin the line feature DLA and the line feature DLB and the X-axis is 45°.

Subsequently, the distance S between the corners closest to each otherin the line feature DLA and the line feature DLB is calculated. Further,a resolution Re (k1×λ/NA) is calculated based on the wavelength λ of theexposure light and the numerical aperture NA of an exposure device and aprocess-dependent parameter k1. Subsequently, for example, it isdetermined whether or not the distance S is not less than 50% of theresolution Re and not more than 300% thereof. When this condition ismet, the following measure is taken as illustrated in FIG. 18: acorrection prohibited region PRA is set in the line feature DLA and acorrection prohibited region PRB is set in the line feature DLB.

The length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB aredetermined based on the arrangement relation between the line featureDLA and the line feature DLB in the XY plane. Since the angle θ1 is 45°,in this case, the following measure is taken: the length AX in theX-axis direction of the correction prohibited region PRA and the lengthAY in the Y-axis direction thereof are set to an identical value; andthe length. BX in the X-axis direction of the correction prohibitedregion PRB and the length BY in the Y-axis direction thereof are alsoset to an identical value.

Subsequently, optical proximity correction is carried out on the linefeature DLA and the line feature DLB with the correction prohibitedregions PRA, PRB excluded. Then shape simulation for a resist pattern iscarried out based on the line features that underwent the opticalproximity correction. In model-based OPC, as mentioned above, thepattern deformation and the shape simulation for a resist pattern arerepeated until a target resist pattern is obtained. Thus the followingprocessing is carried out as illustrated in FIG. 19: with respect to theline feature DLA, a corrected line feature CLA is obtained with thecorrection prohibited region PRA excluded; and with respect to the linefeature DLB, a corrected line feature CLB is obtained with thecorrection prohibited region PRB excluded.

Subsequently, a photomask is manufactured by carrying out electron beamlithography based on the data of the obtained corrected line feature CLAand the data of the obtained corrected line feature CLB. First, a resistfilm for electron beam exposure over a light shield film formed over thesurface of a glass plate is scanned with an electron beam based on thedata. A predetermined pattern containing the corrected line feature CLAand the corrected line feature CLB is thereby drawn. Subsequently, theresist film for electron beam exposure is subjected to predetermineddevelopment and a resist pattern corresponding to the corrected linefeature CLA and the corrected line feature CLB is thereby formed.

Subsequently, the light shield film is etched using the resist patternas a mask. As a result, as illustrated in FIG. 20, a photomask M ismanufactured. The photomask is obtained by forming a photomask linefeature MLA corresponding to the corrected line feature CLA and aphotomask line feature MLB corresponding to the corrected line featureCLB in the light shield film SF. Using the thus manufactured photomaskM, resist applied to a semiconductor substrate is subjected tophotoengraving and development. As illustrated in FIG. 21, consequently,a resist pattern RLA and a resist pattern RLB are formed in the resist(positive resist) R.

In the above-mentioned manufacturing method of a photomask, thefollowing procedure is taken. Features that are close to each other andare estimated to violate a mask rule check after optical proximitycorrection is carried out are extracted. In these features, correctionprohibited regions in which optical proximity correction is not carriedout are set based on the arrangement relation between the patterns.Thereafter, optical proximity correction is carried out. Especially, inthis case, the angle θ1 is 45° and thus the length in the X-axisdirection and the length in the Y-axis direction of each of thecorrection prohibited regions PRA, PRB are set to an identical value. Asa result, a photomask that makes it possible to obtain a target resistpattern (the patterning shape of a film to be processed over asemiconductor substrate) without violating a mask rule check can beobtained. In addition, since a desired resist pattern based on designedvalues is obtained, it is possible to ensure a sufficient depth offocus.

Fifth Embodiment

Description will be given to a more concrete fourth example of themanufacturing method of a photomask. As illustrated in FIG. 22, it willbe assumed that the followings are line features that are close to eachother and estimated to violate a mask rule check when optical proximitycorrection is carried out: a line feature DLA, WA in width and a linefeature DLB, WB in width. In addition, it will be assumed that the angleθ2 formed by a line segment connecting the corners closest to each otherin the line feature DLA and the line feature DLB and the X-axis issmaller than 45°.

Subsequently, the distance S between the corners closest to each otherin the line feature DLA and the line feature DLB is calculated. Further,a resolution Re (k1×λ/NA) is calculated based on the wavelength λ, ofthe exposure light and the numerical aperture NA of an exposure deviceand a process-dependent parameter k1. Subsequently, for example, it isdetermined whether or not the distance S is not less than 50% of theresolution Re and not more than 300% thereof. When this condition ismet, the following measure is taken as illustrated in FIG. 23: acorrection prohibited region PRA is set in the line feature DLA and acorrection prohibited region PRB is set in the line feature DLB.

The length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB aredetermined based on the arrangement relation between the line featureDLA and the line feature DLB in the XY plane. Since the angle θ2 issmaller than 45°, in this case, the following measure is taken: thelength AY in the Y-axis direction of the correction prohibited regionPRA is set to a value larger than the length AX in the X-axis directionthereof; and the length BY in the Y-axis direction of the correctionprohibited region PRB is set to a value larger than the length BX in theX-axis direction thereof.

Subsequently, optical proximity correction is carried out on the linefeature DLA and the line feature DLB with the correction prohibitedregions PRA, PRB excluded. Then shape simulation for a resist pattern iscarried out based on the line features that underwent the opticalproximity correction. In model-based OPC, as mentioned above, thepattern deformation and the shape simulation for a resist pattern arerepeated until a target resist pattern is obtained. Thus the followingprocessing is carried out as illustrated in FIG. 24: with respect to theline feature DLA, a corrected line feature CLA is obtained with thecorrection prohibited region PRA excluded; and with respect to the linefeature DLB, a corrected line feature CLB is obtained with thecorrection prohibited region PRB excluded.

Subsequently, a photomask is manufactured by carrying out electron beamlithography based on the data of the obtained corrected line feature CLAand the data of the obtained corrected line feature CLB. First, a resistfilm for electron beam exposure over a light shield film formed over thesurface of a glass plate is scanned with an electron beam based on thedata. A predetermined pattern containing the corrected line feature CLAand the corrected line feature CLB is thereby drawn. Subsequently, theresist film for electron beam exposure is subjected to predetermineddevelopment and a resist pattern corresponding to the corrected linefeature CLA and the corrected line feature CLB is thereby formed.

Subsequently, the light shield film is etched using the resist patternas a mask. As a result, as illustrated in FIG. 25, a photomask M ismanufactured. The photomask is obtained by forming a photomask linefeature MLA corresponding to the corrected line feature CLA and aphotomask line feature MLB corresponding to the corrected line featureCLE in the light shield film SF. Using the thus manufactured photomaskM, resist applied to a semiconductor substrate is subjected tophotoengraving and development. As illustrated in FIG. 26, consequently,a resist pattern RLA and a resist pattern RLB are formed in the resist(positive resist) R.

In the above-mentioned manufacturing method of a photomask, thefollowing procedure is taken. Features that are close to each other andare estimated to violate a mask rule check after optical proximitycorrection is carried out are extracted. In these features, correctionprohibited regions in which optical proximity correction is not carriedout are set based on the arrangement relation between the features.Thereafter, optical proximity correction is carried out. Especially, inthis case, the angle θ2 is smaller than 45° and thus the length in theY-axis direction of each of the correction prohibited regions PRA, PRBis set to a value larger than the length in the X-axis directionthereof. As a result, a photomask that makes it possible to obtain atarget resist pattern (the patterning shape of a film to be processedover a semiconductor substrate) without violating a mask rule check canbe obtained. In addition, since a desired resist pattern based ondesigned values is obtained, it is possible to ensure a sufficient depthof focus.

Sixth Embodiment

Description will be given to a more concrete fifth example of themanufacturing method of a photomask. As illustrated in FIG. 27, it willbe assumed that the followings are line features that are close to eachother and estimated to violate a mask rule check when optical proximitycorrection is carried out: a line feature DLA, WA in width and a linefeature DLB, WB in width. In addition, it will be assumed that the angleθ3 formed by a line segment connecting the corners closest to each otherin the line feature DLA and the line feature DLB and the X-axis issmaller than 45°.

Subsequently, the distance S between the corners closest to each otherin the line feature DLA and the line feature DLB is calculated. Further,a resolution Re (k1×λ/NA) is calculated based on the wavelength λ of theexposure light and the numerical aperture NA of an exposure device and aprocess-dependent parameter k1. Subsequently, for example, it isdetermined whether or not the distance S is not less than 50% of theresolution Re and not more than 300% thereof. When this condition ismet, the following measure is taken as illustrated in FIG. 28: acorrection prohibited region PRA is set in the line feature DLA and acorrection prohibited region PRB is set in the line feature DLB.

The length in the X-axis direction and the length in the Y-axisdirection of each of the correction prohibited regions PRA, PRB aredetermined based on the arrangement relation between the line featureDLA and the line feature DLB in the XY plane. In this case, the angle θ3is smaller then 45° and both the line feature DLA and the line featureDLB are arranged in parallel with the X-axis. Therefore, the length AXin the X-axis direction of the correction prohibited region PRA is setto a value larger than the length AY in the Y-axis direction thereof.The length BX in the X-axis direction of the correction prohibitedregion PRB is set to a value larger than the length BY in the Y-axisdirection thereof.

Subsequently, optical proximity correction is carried out on the linefeature DLA and the line feature DLB with the correction prohibitedregions PRA, PRB excluded. Then shape simulation for a resist pattern iscarried out based on the line features that underwent the opticalproximity correction. In model-based OPC, as mentioned above, thepattern deformation and the shape simulation for a resist pattern arerepeated until a target resist pattern is obtained. Thus the followingprocessing is carried out as illustrated in FIG. 29: with respect to theline feature DLA, a corrected line feature CLA is obtained with thecorrection prohibited region PRA excluded; and with respect to the linefeature DLB, a corrected line feature CLB is obtained with thecorrection prohibited region PRB excluded.

Subsequently, a photomask is manufactured by carrying out electron beamlithography based on the data of the obtained corrected line feature CLAand the data of the obtained corrected line feature CLB. First, a resistfilm for electron beam exposure over a light shield film formed over thesurface of a glass plate is scanned with an electron beam based on thedata. A predetermined pattern containing the corrected line pattern CLAand the corrected line pattern CLB is thereby drawn. Subsequently, theresist film for electron beam exposure is subjected to predetermineddevelopment and a resist pattern corresponding to the corrected linefeature CLA and the corrected line feature CLB is thereby formed.

Subsequently, the light shield film is etched using the resist patternas a mask. As a result, as illustrated in FIG. 30, a photomask M ismanufactured. The photomask is obtained by forming a photomask linefeature MLA corresponding to the corrected line feature CLA and aphotomask line feature MLB corresponding to the corrected line featureCLB in the light shield film SF. Using the thus manufactured photomaskM, resist applied to a semiconductor substrate is subjected tophotoengraving and development. As illustrated in FIG. 31, consequently,a resist pattern RLA and a resist pattern RLB are formed in the resist(positive resist) R.

In the above-mentioned manufacturing method of a photomask, thefollowing procedure is taken. Features that are close to each other andare estimated to violate a mask rule check after optical proximitycorrection is carried out are extracted. In these features, correctionprohibited regions in which optical proximity correction is not carriedout are set based on the arrangement relation between the features.Thereafter, optical proximity correction is carried out. Especially, inthis case, the angle θ3 is smaller than 45° and both the line featureDLA and the line feature DLB are arranged in parallel with the X-axis.Therefore, the length AX in the X-axis direction of the correctionprohibited region PRA is set to a value larger than the length AY in theY-axis direction thereof. In addition, the length BX in the X-axisdirection of the correction prohibited region PRB is set to a valuelarger than the length BY in the Y-axis direction thereof. As a result,a photomask that makes it possible to obtain a target resist pattern(the patterning shape of a film to be processed over a semiconductorsubstrate) with designed values without violating a mask rule check canbe obtained. In addition, since a desired resist pattern based ondesigned values is obtained, it is possible to ensure a sufficient depthof focus.

The above-mentioned photomasks (FIG. 20, FIG. 25, FIG. 30) containingeach line feature can be used, for example, when a wiring groove or thelike for forming copper wiring is formed by a damascene method.Meanwhile, the photomasks obtained by patterning a light shield film sothat portions where the light shield film is left and portions where itis removed are inverted with respect to the photomasks illustrated inFIG. 20, FIG. 25, and FIG. 30 are also used. These photomasks can beused to form, for example gate wiring or the like.

In the description of each of the above embodiments, the conditions fordetermining whether to set correction prohibited regions PRA, PRB arejust an example; and they are set to appropriate values according to themanufacturing process or the like for each photomask. In the descriptionof each of the above embodiments, the following cases have been taken asexamples: cases where after correction prohibited regions PRA, PRB areset, corrected hole features CHA, CHB or corrected line features CLA,CLB are obtained based on model-based OPC. Instead, corrected holefeatures or corrected line features may be obtained by correcting databy a preset amount of correction by rule-based OPC.

Seventh Embodiment

Description will be given to an example of the manufacturing method of asemiconductor device to which the above-mentioned photomasks is appliedbased on the planar layout (designed values) of the semiconductor deviceillustrated in FIG. 32. A photomask containing hole features is appliedto the patterning of resist to form openings in an interlayer insulatingfilm when contact plugs CH1, CH2 close to each other, shown in thebroken line frame on the right of the drawing, are formed.

In this case, resist (positive resist) REC is applied to the surface ofan interlayer insulating film 3 covering a transistor TR and the likeplaced over the surface of a semiconductor substrate 1 as illustrated inFIG. 33. This resist REC is subjected to photoengraving using theabove-mentioned photomask containing hole features and then developmentis carried out. As a result, a resist pattern RH1 and a resist patternRH2 close to each other are formed in the resist REC. Thereafter, usingthe resist REC as a mask, the interlayer insulating film 3 is subjectedto anisotropic etching to form openings (not shown). These openings arefilled with a predetermined conductive member and the contact plugs CH1,CH2 are thereby formed.

Meanwhile, a photomask containing line features is applied to thepatterning of resist to form wiring grooves in the interlayer insulatingfilm when wirings ML1, ML2 close to each other are formed. In this case,the resist (positive resist) REC covering the interlayer insulating film3 is subjected to photoengraving using the above-mentioned photomask(Refer to FIG. 30) containing line features as illustrated in FIG. 34and then development is carried out. As a result, a resist pattern REL1and a resist pattern REL2 close to each other are formed as openpatterns (cutout patterns) in the resist REL.

Thereafter, using the resist REL as a mask, the interlayer insulatingfilm 3 is subjected to anisotropic etching to form wiring grooves (notshown). A copper film or the like is so formed as to fill these wiringgrooves and the copper films are subjected to chemical mechanicalpolishing. As a result, the wirings ML1, ML2 are formed.

As a photomask containing line features, the following photomask may beused to carry out photoengraving and development: a photomask obtainedby patterning a light shield film so that portions where the lightshield film is left and portions where it is removed are inverted withrespect to the photomask illustrated in each of FIG. 20, FIG. 25, andFIG. 30. In this case, resist patterns RL1, RL2 arising from linearlyleft resist are formed in the resist REL applied to the surface of theconductive film 4 as illustrated in FIG. 35. Thereafter, using theresist REL as a mask, the conductive film 4 is subjected to anisotropicetching and the wirings ML1, ML2 are thereby formed. The photomaskscontaining line features in such a mode can be applied when theelectrode wirings EL illustrated in FIG. 32 are formed.

In the manufacturing method of a semiconductor device to which theabove-mentioned photomasks are applied, a desired resist pattern basedon designed values can be obtained and thus it is possible to ensure adepth of focus. As a result, the margin in photoengraving can beenhanced regardless of any variation, such as a step in a base material,from process to process.

The embodiments disclosed here are just examples and the invention isnot limited to them. The invention is shown by WHAT IS CLAIMED IS, notby the above description, and it is intended to include everymodification within the meaning and scope equivalent to claims.

The invention is effectively utilized to manufacture a photomaskcontaining hole features or line features and the manufacture of asemiconductor device using this photomask.

1-6. (canceled)
 7. A manufacturing method of a semiconductor device,comprising the steps of: forming a film to be processed over the mainsurface of the semiconductor substrate; applying resist to the surfaceof the film to be processed; photoengraving the resist using a photomaskcontaining proximity photomask features close to each other; subjectingthe photoengraved resist to development to form a resist patterncorresponding to the proximity photomask patterns; and processing thefilm to be processed using the resist pattern as a photomask and therebyforming a film-to-be-processed pattern corresponding to the proximityphotomask patterns in the film to be processed, wherein the proximityphotomask features in the photomask are formed by: extracting proximitydesign features that are brought close to each other when opticalproximity correction is carried out and estimated not to be stablyresolved as a photomask pattern and to violate a mask rule check; in theextracted proximity design features, setting correction prohibitedregions where optical proximity correction is not carried out, based onthe distance between the features obtained from the proximity designfeatures and a resolution obtained from the wavelength of the exposurelight and the numerical aperture of an exposure device; carrying outoptical proximity correction on the proximity design features with thecorrection prohibited regions excluded to obtain corrected proximitypatterns; and carrying out electron beam lithography based on theobtained corrected proximity patterns.
 8. The manufacturing method of asemiconductor device according to claim 7, wherein the step of formingthe film to be processed includes a step of forming a first insulatingfilm, wherein the step of carrying out the photoengraving includes astep of photoengraving the resist using as the photomask a firstphotomask containing a first open photomask pattern and a second openphotomask pattern close to each other, wherein the step of forming thefilm-to-be-processed pattern includes a step of forming a first openingcorresponding to the first open photomask pattern in the firstinsulating film and forming a second opening corresponding to the secondopen photomask pattern in the same, and wherein the step of forming aconductive member includes a step of forming a first contact portion inthe first opening and forming a second contact portion in the secondopening.
 9. The manufacturing method of a semiconductor device accordingto claim 7, wherein the step of forming the film to be processedincludes a step of forming a second insulating film, wherein the step ofcarrying out the photoengraving includes a step of photoengraving theresist using as the photomask a second photomask containing a first linephotomask pattern and a second line photomask pattern close to eachother, wherein the step of forming the film-to-be-processed patternincludes a step of forming a first groove portion corresponding to thefirst line photomask pattern in the second insulating film and forming asecond groove portion corresponding to the second line photomask patternin the same, and wherein the step of forming the predeterminedconductive member includes a step of forming a first wiring in the firstgroove portion and forming a second wiring in the second groove portion.10. The manufacturing method of a semiconductor device according toclaim 7, wherein the step of forming the film to be processed includes astep of forming a conductive film, wherein the step of carrying out thephotoengraving includes a step of photoengraving the resist using as thephotomask a third photomask containing a third line photomask patternand a fourth line photomask pattern close to each other, and wherein thestep of forming the film-to-be-processed pattern includes a step offorming a third wiring corresponding to the third line photomask patternin the conductive film and forming a fourth wiring corresponding to thefourth line photomask pattern in the same.